This invention is directed to the field of shipping, storage and delivery of bulk materials. In particular, the invention is directed to a container for storing bulk materials which is capable of being stacked while filled with the very dense bulk materials and then disassembled for convenient storage and return shipping when not filled with bulk materials.
Bulk materials, such as iron powder and the like, often must be shipped from one location to a remote location. The shipping of these materials creates unique difficulties because they are very dense and thus require a very strong container. Further, due to the small size of the discreet elements of the material, they effectively "flow" which can result in leakage and loss of the material. This is of particular concern since the bulk materials are often costly.
Typically, bulk materials are shipped in cardboard containers having an octagonal profile. The containers lack adequate structural stability and thus metal bands are required to insure the integrity of the container once filled. This is particularly true since the bending corners of the containers are integrally formed with the side walls. They are made of the same material. Thus, the side walls are made of a flexible material, reducing its structural strength. Once the containers are filled with the bulk material, they are loaded onto a truck or train car. The filled containers are placed on a wooden pallet which, in turn, is lifted and moved by a forklift. There is some risk that, during moving, the container will fall off the pallet. Of course, the container could be secured to the pallet using straps and the like but this would require additional man-hours (and the attendant costs) to ensure it is done properly. Even if secured, this technique requires the use of large numbers of wooden pallets which can be costly and are susceptible to breaking, especially under the heavy load of a filled container.
Storage space in a truck or train is at a premium. Consequently, it is important that the bulk-filled containers be packed together tightly. The large pallets limit how closely the containers can be loaded. Even with the metal bands, the cardboard containers are not strong enough to be stacked one on top of the other. Further, should one of the containers tip over, the sides can be easily punctured allowing material to escape. Once used, the cardboard containers are thrown away, creating a large amount of waste. Thus, the current cardboard containers have been found to be unacceptable for numerous reasons.
Various containers have been developed over the years in an effort to address these problems. U.S. Pat. No. 4,742,951 is directed to a container for bulk flowable materials. An octagonal-shaped cardboard sleeve is attached to a bottom end cap. The adjacent panels of the sleeve are connected along elongate edges. A tubular inner member which is designed to withstand the pressure of the contained material is inserted inside the octagonal sleeve. A top end cap is attached to the top of the sleeve.
U.S. Pat. No. 4,927,026 is directed to pallet box. Side walls of a container are hinged to the surface of a pallet. A tubular cardboard sleeve is positioned about the side walls and maintains the container shape. The container can be formed by criss-crossing panels attached to the pallet.
U.S. Pat. No. 5,178,275 is directed to an eight-sided columnar container for supporting bulk materials in sacks. An eight-sided collapsible sleeve is mounted to a pallet. Tabs are positioned along the bottom edge of each side of the container. Alternating tabs are bent inward or outward. The sacks of materials are disposed within the sleeve and a cap may be positioned on top of the sleeve.
U.S. Pat. No. 5,441,154 is directed to a integrated paperboard container and pallet system. The wall portion of the container has a polygonal-shaped interior cavity. At least one tab is formed at the bottom of one of the walls. The deck portion has a planar member with an upper side forming a floor surface and a lower side forming a support surface. Edges are mounted to the planar member and have the same polygonal shape as the wall portion. Openings are positioned in the planar member to receive any tabs. The planar member is designed to be mounted to a pallet, if desired. The wall portion can be folded when it is not attached to the planar member.
U.S. Pat. No. 4,511,080 is directed to interlocking end closure flaps on collapsible eight-sided receptacle. The receptacle is formed of a single blank of foldable sheet material. The flaps positioned along the bottom edges of the receptacle fold over to form the bottom of the container.
U.S. Pat. No. 5,269,414 is directed to an intermediate bulk container. The side walls of the container are made of a rigid material and are hinged to the base using one- or two-directional hinges. Sealing strips or separate bags are provided to prevent any leaking of material through the hinge. The bottom panel of the container may be ramped to direct the flow of material from the container. A cutting means can be provided at the exit of the container to allow for opening any internal bag holding the material.
U.S. Pat. No. 5,253,763 is directed to a collapsible container. The walls of the container are mounted by long, horizontal hinges attached to the walls. This container can be palletized.
U.S. Pat. No. 5,507,392 is directed to a pallet container with adapter frame. A hinged support insert is provided that folds upon itself using both internal and external hinges. The container may be provided with a plastic, sloped bottom.
None of these patents fully address the problems resolved by the instant invention.